BYU CS/ECEn 124 Chapter 3 - Digital Logic 2 History of the Transistor  Around 1945, Bell Labs scientists discovered that silicon was comprised of two distinct regions differentiated by the way in which they favored current flow.  The area that favored positive current flow they named "p" and the area that favored negative current flow they named "n".  The transistor effect describes the change from a condition of conductivity (switched “on”, full current flow) to a condition of insulation (switched “off”, no current flow). The Transistor

BYU CS/ECEn 124 Chapter 3 - Digital Logic 8 The Inverter in 10 out0 10 1 on off 1 100 on off This is a truth-table. It tells what the output will be for all combinations of the inputs. Inverter Symbols Symbols are abstractions! Digital Logic Devices In out0 1 10